Microemulsions of Mannich (alk)acrylamide polymers are well known and have become increasingly important in the separation of solids from solids dispersions. These microemulsions provide faster and more complete isolation of solids from such media as municipal and industrial sludges, cellulosic suspensions such as those found in paper production e.g. paper waste, various organic and inorganic suspensions e.g. refining wastes, food wastes etc. Particulars of these microemulsions can be found in the following U.S. Pat. Nos. 4,956,399; 5,037,881 and 5,132,023.
One of the problems exhibited by these microemulsions is their tendency to possess a low Flash Point such that storage thereof over periods of time presents difficulties and hazards in handling and use especially in the presence of heat or an open flame.
Accordingly, there exists a need for Mannich (alk)acrylamide polymer-based microemulsions which have a Flash Point such that the dangers attendant low Flash Point microemulsions are obviated or reduced.
It has now been discovered that the Flash Point of Mannich (alk)acrylamide polymer based microemulsions can be satisfactorily adjusted (raised) to an acceptable value by the addition thereto of a material which accomplishes this function. The result is microemulsions which can be stored, handled and used for a reasonable period of time without fear of bursting into flame.